Preheat oven to 200 degrees Celsius. Grease refractory form with butter. Wash cod fillet, dry, drizzle with lemon juice, season with salt and white pepper. Put fillets in a single layer form. Cut tomatoes into small cubes, break off the leaves of basil. Mix the tomatoes and basil cream, salt and pepper, pour over the fish. Cook in the oven for 15 minutes.